a-Glucan Phosphorylase: Variability in Solanaceae Species

a -Glucan phosphorylase is one of the key enzyme in starch degradation and abiotic stress tolerance in plants. In this work for the first time variability in exon II – exon IV of the a-glucan phosphorylase gene Pho1 has been characterized in 18 Solanum species of section Petota (including subsections Estolonifera, Potatoe, Lycopersicon), section Crinitum (S. sisimbrifolium), section Melongena (S. melongena), section Minon (S. pseudocapsicum), section Dulcamara (S. dulcamara), section Solanum (S. nigrum) and eight species of Nicotiana, Petunia and Capsicum genera, taken into analysis as outgroups. Overall, 44 sequences of 31 species were analyzed. The length of the obtained DNA fragments from 3’-end of exon II to 5’-end of exon IV ranged from 672 (in Capsicums) to 754 bp (in S. melongena), with a highly variable introns II and III, saturated with numerous SNPs and extended indels (up to 38 bp).  In total  362 SNPs  and 25 indels have been detected.  High (29.3%) level of coding sequence polymorphism has been revealed and 83 SNPs have been identified in exons. 34 SNPs that have been detected in Pho1 sequences caused 20 synonymic and 14 non -synonymic amino acid substitutions. As a result each taxonomical group have been characterized a number of taxon-specific SNPs and amino acid substitutions. Estimated genetic distances and reconstructed phylogenic trees showed concordance with previous classifications of the investigated species and confirmed the utility of the Pho1 locus for taxonomic identification and evolution studies of Solanaceae. The work was supported by FTP ¹16.Ì04.12.0006 and RFBR 11-04-00446.